Of the dielectric elements of the type, those having a high dielectric constant are utilized in all electronic instruments such as computers, mobile telephones and others, and act in the core of electronic instruments, for example, in the memory, the transistor gate insulating film or the like thereof. The current remarkable development of electronic instruments such as personal computers, mobile telephones and others is supported by the advanced functions of dielectric elements. Heretofore, the development of dielectric elements and the advanced functions thereof have been realized by the technology of microstructuring and high-integration (top-down technology) based on the forefront of film formation technology and semiconductor fabrication technology. For example, in DRAM and transistor, the thickness of the dielectric thin film is being reduced year by year, as aiming at capacity increase; and a nanometer-order thin film structure has already been used everywhere in the devices. However, physical and economical limits are approaching close at hand in the microstructuring and high-density integration increase technology; and for brake-through to realization of next-generation devices, it is now indispensable to unite the creation of novel dielectric materials and nanotechnology.
Of many dielectric materials, perovskite-type oxides have excellent dielectric properties (specific dielectric constant, at least 200); and from the beginning of 1990's, application studies of the oxides to electronic devices such as memory cells, transistors and others have been made.
Recently, development of capacitor insulating films for high-capacity DRAM memory cells and monolithic microwave integration circuits, using perovskite-type oxides, is positively made; and a trial of applying high-dielectric perovskite-type oxides such as (Ba,Sr)TiO3, Pb(Zr,Ti)O3 or the like, in place of current SiO2 or SiNx, has proven good practicability of those oxides.